Car tyres made from dandelions

As natural rubber production falls short of demand, it’s time to consider
alternatives, like the dandelion.

Sap of the future: we could soon see tyres made from Taraxacum kok-saghyz

By Ian Hodgson

10:56AM GMT 12 Dec 2012

Mention dandelion and a shudder wriggles down most gardeners’ spines. Scourge of lawns, borders, patios and allotments, they’re a major reason why we spend a fortune on weed killer or hours bent double, extracting their thong-like roots. Now, a species of Russian dandelion is set to become one of the most important plants on the planet, propping up civilisation with rubber made from the glutinous, milky sap found in its roots.

In July this year, Indian-Dutch company Apollo Vredestein rolled out the first prototype tyres produced from European-grown rubber. If tests go well, they hope to start full production in 2015. The dandelion, Taraxacum kok-saghyz (TKS), is one of three plants currently being investigated by various international consortia, made up of government agencies, big business and scientific research establishments, locked in a multi-million pound scramble to find alternatives to natural rubber.

Increasing demand

World supplies of natural rubber are falling short of demand, which is driven by the needs of developing nations such as China, India, Brazil and countries of the former Soviet Union. Around 80 per cent of the world’s natural rubber is produced from plantations of the tropical tree, Hevea brasiliensis, primarily located in Malaysia, Indonesia, Thailand and South America.

According to The Rubber Economist, these countries produce 10.9 million tons of rubber, worth £32.6 billion, every year. Synthetic rubber, mainly produced from fossil fuels, weighs in at almost 15 million tons and is worth £31.5 billion. With demand projected to outstrip supply by around 20 per cent in 2020, there are serious concerns for the future. Falling yields of natural rubber, the monopoly of producer countries, crop diseases, changing climate and dwindling oil reserves paint an unsettling picture.

Native to Uzbekistan and Kazakhstan and discovered in 1931, TKS is a foot-tall yellow-flowered dandelion. It will grow in a range of soils, but prefers the cool conditions of its homeland and similar locations, such as northern Europe.

During the Thirties, Stalin led a drive to make the Soviet Union independent of imported natural rubber. TKS soon caught the attention of Soviet scientists. With the outbreak of the Second World War it became strategically important. As rubber plantations fell into the hands of the Japanese, the US Emergency Rubber Programme trialed TKS in 28 states. It was also widely planted in Canada; in Britain experiments were conducted at Kew.

Although initially sceptical, preferring to rely on synthetic rubber, the Nazis began to farm Russian TKS in concentration camps, using forced labour.

Once post-war supplies of cheap natural rubber were restored, the industry was abandoned, although the Soviet Union continued research until Stalin’s death in 1953. China too, persevered, and produced their first tyres the same year.

Vintage tyre posters (ALAMY)

Improving yields

Early on it was discovered that, although TKS produced rubber of comparable quality to Hevea brasiliensis, yield was variable. Spurred on by renewed global interest, this fuelled a search for the most productive wild forms. Aided by conventional plant breeding techniques, selection has raised yield from 1.4 per cent to 8.9 per cent of dry weight, with some clones now exceeding the 10 per cent target required for commercial use.

The advantage of TKS over other plants is that it has a wide climatic tolerance, can be grown as a short term or even annual crop, and harvested and processed mechanically. This enables it to be farmed according to need, which tree-sourced rubber cannot.

It also creates the sugar-substitute inulin as a by-product, and is being investigated as a potential biofuel.

Other plants being investigated for second natural rubber (SNR) are the American guayule (Parthenium argentatum), and China’s hardy rubber or gutta-percha tree, Eucommia ulmoides, which yields a glutinous sap, termed eu-gum.

The American model

Guayule (from the native Indian name for rubber), is another member of the daisy family, a 3ft silver-leaved shrubby perennial thriving in the Mediterranean climate of the south western United States and northern Mexico. Although initially wild-sourced, it was field-grown from 1910 into the Thirties. As with TKS, war raised its importance. The US government invested around $40 million to support 32,000 acres of guayule.

When the war ended the industry was terminated as the US focused on imports of natural and home-produced synthetic rubber.

Recent commercial interest has resulted in high-yielding forms being farmed on a short, year-round cycle, the crop being cut to the ground after two years, stimulating a flush of new shoots for further harvests. Unlike Hevea, rubber from guayule is hypoallergenic (as is that from TKS) and so is preferred for manufacturing medical, dental and cosmetic products and appliances.

Research has also identified that the green waste, termed bagasse, can be used as a fuel, comparable to charcoal and is also a potential source of ethanol and synthetic gas.

Chinese history

Eucommia is a living fossil, the only remaining member of an ancient family of trees once widespread in North America, Europe and Asia, until the last Ice Age caused the extinction of all but this single species. Found in the mountains of central China, this deciduous elm-like tree, reaches 40-60ft, is drought-tolerant and hardy to -30C. Although almost extinct in the wild, it is estimated that 95 per cent of the world’s population of Eucommia inhabit the 300,000 hectares of farmed forest in central China. Its bark has been used in Chinese medicine for thousands of years to cure ailments such as arthritis, osteoporosis and hypertension. All parts of the tree contain rubber-producing sap, the leaves 1-3 per cent, the bark 6-10 per cent and the seeds 10-12 per cent, but it is the leaves and seeds which will be harvested commercially.

Britain left behind

Tyre producers such as Bridgestone, Ford and Apollo-Vredestein have all invested heavily in the research and commercial and sustainable development of TKS and guayule. Apollo is an industry partner of the EU-based Production and Exploitation of Alternative Rubber and Latex Sources (EU-Pearls), the European consortium involving 10 partners in seven countries: France, Germany, Spain, Italy, Holland, the Czech Republic, Kazakhstan and the United States. Crops will be grown where most suited. The US will grow TKS in the north and already grows guayule in the south, while Canada recently approved growing TKS.

In Europe, Germany grows TKS, with Holland extracting the rubber for the Apollo prototype tyres. China plans to grow all four, TKS in the north, Eucommia and guayule in the centre and Hevea in the south.

So where is the UK in all of this? Well, nowhere. Our native dandelions don’t contain enough rubber to be commercially useful. We’re not part of any European initiative. Agencies that would be involved if we were say there is no political or commercial will to become involved. So while the rest of the world drives this technology forward, the dandelions of Britain will continue to reign as pests supreme.